There are a number of off-line options that you can use to manipulate images Here are some freely available options to start with listed in order of complexity of use
Microsoft Picture Manager can be found in the Office suite under Microsoft Tools. This is a basic image editor that is also okay for doing batch resize and renaming.
Paint is another Microsoft application that enables you to annotate, crop and resize images though it is limited in its capabilities. You can find Paint on your PC under Accessories in your All Programs list.
Irfanview is a quite useful tool for more than just manipulating images. It is a free download from http://www.irfanview.com/. As well as enabling batch resizing etc you can also add text and shapes to images.
Paint.Net is another free download from http://www.getpaint.net/ that enables you to work with layers, unlimited undo, special effects, and a wide variety of other tools
If you are using a Mac then Skitch is a really great download app that enables you to annotate over and add features to your images. If you want to resize images, add some simple annotations and/or adjust elements of the image, then Preview on the Mac also has these functions.
The Gimp is the free alternative to Photoshop and the like. It can appear quite tricky to use at first but if you persist then you can achieve some stunning image effects. The Gimp can be downloaded from http://www.gimp.org/
Here are some freely available options to start with listed in order of complexity of use
As well as enabling batch resizing etc you can also add text and shapes to images.
If you want to resize images, add some simple annotations and/or adjust elements of the image, then Preview on the Mac also has these functions.
The Gimp can be downloaded from http://www.gimp.org/